The present invention relates to a demountable modular floor for watertight raised decks. More particularly, this invention relates to a floor structure consisting of a plurality of modularly assemblable composite slabs made of steel sheet and concrete provided with a drainage system for collecting and conveying the rainwater between the slabs. Such floor structure allows a rapid setting up of the raised deck and, at the same time, it affords the total dismantling thereof and prevents any seepage or leakage of water towards the underlying area.
As it is known, constructions of one or more raised floors or decks suited to be set up in a short time and with restricted economic resources are becoming quite interesting particularly for building more or less temporary parking lots, as an alternative to conventional multistorey underground and/or raised car park constructions. If it is desired to maximise the advantages offered by such structures, however, it is necessary that the assembling times and costs be really competitive, without any negative impact on the quality and duration of the resulting work.
A structure that allows the above objects to be achieved is disclosed in the European patent No. 0364414, owned by the instant Applicant. Such patent concerns a modular system that can be easily assembled for setting up in extremely short times a raised floor to be used as a parking place for cars, and that can also be disassembled and recovered for reutilisation, for instance in a different location. The structure substantially consists of modular units each of which comprises a rectangular or square composite floor element, surrounded by four edge beams and held up at its corners by four vertical supporting elements or pillars that bear said edge beams through corresponding node elements or capitals, special bases for resting on the ground being provided under said vertical supporting elements, while a system of ties and/or struts transversely strengthens the structure.
Each of said vertical supporting elements ends, at a level corresponding to the base, in a threaded joint suited to enable the total length of the vertical element to be adjusted. Said base also comprises a hinge device, particularly consisting of a spherical joint, enabling the base plate to lie down according to the slope of the ground surface, while the overlying supporting element may take a perfectly vertical position. This double adjustment system makes it possible to install the modular structure also on not previously levelled, uneven grounds, and with no need to provide any foundation works. Thus, the concerned structure is set up by assembling the modular units beside one another, with adjacent modules sharing in turn the relevant beams and supporting elements, so as to obtain a raised deck suitable for use as a parking lot, taking any desired shape and size.
In the illustrative embodiments disclosed in the European patent No. 0364414, the modular slabs of the floor are made of a double layer consisting of a corrugated steel sheet of suitable thickness as the load-bearing component, covered by a panel of light and strong material as the paving component, preferably made of suitably treated ply-wood. This approach is proposed in order to allow the use of light elements, to be assembled on the same site where the parking structure is to be built, such elements involving relatively reduced transportation costs and being easily moved within the building yard, by hand or by small lifting trucks.
In the practical construction of modular parking lots according to the above patent provided with composite floors of corrugated steel sheet and wood (preferably birch ply-wood, treated with synthetic resins for waterproofing purposes), the wood panel is connected to the underlying steel sheet by means of metal channel sections with a omega(xcexa9)-shaped cross-section, that are mounted along the edges of two adjacent panels. The omega-shaped channels are perforated in the groove portion of the section in order to enable their connection to the underlying corrugated steel sheet by means of bolts. The corrugated steel sheet, in turn, is correspondingly perforated along the contact area with the omega-shaped section. This method of mounting the wood panels (aimed, as it is apparent, at assuring the full demountability of the composite floor slabs) results in avoiding any need to perforate the treated wood panel, but, on the other hand, it necessarily involves the perforation of the load-bearing corrugated steel sheet on the building yard.
The corrugated steel sheet is also utilised, in the above-mentioned embodiments, to collect the rainwater under the said wood panel. As the floor is laid slightly slanting by acting on the length of the adjustable pillars of the structure, the water can be conveyed, flowing in the channels of the corrugated sheet, toward one or more peripheral edges of the raised deck, to be collected in edge eaves having conduits branching therefrom for drainage on the ground.
The embodiment with composite floor made of corrugated steel sheet and wood is especially advantageous in view of the relative ease of transportation of the construction components, which allows not to increase too much the construction costs in case of installations in sites very far from the factory or only reachable by sea. Furthermore, such approach has been found to be effective in respect of the modular versatility, that results from the possibility of easily cutting the floor component on the building yard in order to accommodate any size variation of the structural module. Actually, it should be noted that the concerned structure, although being commercially proposed with a standard modularity, should also be such as to meet the various requirements that can be put forward in particular cases. By way of example, the modular structure should be adapted to fulfil the various national rules in respect of the standard size of the vehicle parking stalls or of the roadway width for manoeuvring the vehicles.
In spite of the above advantages, however, the floor slab made of metal sheet and wood panels has the drawback of not affording a long durability of the parking surface, firstly, in view of the need to perforate the steel sheet for connecting it with the metal sections holding the wood panels in place. The perforation makes the steel sheet subject to corrosion and, as said operation is necessarily carried out during the assembling stage, it is not possible to perform a new galvanisation process on the metal sheet after perforation. The corrosive attack is remarkably enhanced not only by the rainwater that is collected within the corrugated steel sheet, but also by the condensate forming in a conspicuous amount in the contact area between the steel sheet and the panel. Secondly, the durability of the floor is strongly jeopardised by the scarce wear resistance of the wooden paving surface, notwithstanding any previous treatment of such surface. In strict dependence on the overall utilisation of the parking structure and on their location in the paving area, the wood panels are subject to such a wear deterioration as to make it often necessary to substitute the damaged ones, especially on the aisles and on the manoeuvring areas.
A further critical element is due to the fact that the wood panel mounted on the corrugated metal sheet makes the floor highly noisy at the passage of the vehicles thereupon, because the coupling of the two above elements together acts as a resonance box.
A second approach considered for producing the floor of the structure according to the European patent No. 0364414 involves the use of single precast elements of reinforced concrete, to be manufactured in factory and to be installed in nearly finished condition. In this case, the reinforced concrete slabs or plates forming the modular units of the floor are cast in suitably shaped metal formworks. Holes and further engagement means are provided in the moulding in order to enable the resulting piece to be removed from the metal formwork upon setting, as well as for transportation and installation purposes.
The concerned concrete slabs are mounted on the bearing structures of the modular parking structure without any casting on the installation site, so as to afford a complete reutilisation of the materials when the parking structure is to be disassembled and transferred. Any connection between the elements, therefore, should not be permanent and, at the same time, it should enable the rainwater to be collected and to flow down without causing any leakage on the underlying area. To this aim, water collecting gutters and eaves are provided between the slabs, covered by an upper metal grid and extending in a first one of the two directions of the lattice formed by the floor slabs arranged side by side. In the direction orthogonal to the first one, conversely, a joint between adjacent slabs is provided by means of complementary steps having a sealing gasket interposed therebetween. Further, in order to improve the sealing effect, the vertical slit between two adjacent slabs is filled with an easily removable sealing material.
The proposed system eliminates the main drawbacks of the first floor system described above, firstly because the thickness and the compactness of the concrete panel actually eliminate the noisiness problem. Secondly, any wear of the paving surface, made of a cement-based material, is noticeably reduced, also by virtue of a layer of resin or of a bituminous conglomerate which is laid upon the concrete to protect it both from wear due to running vehicles and from the rainwater.
However, the floor structure made of precast reinforced concrete is not free from other drawbacks. Among these, particularly critical have been found to be the cost of transporting the slabs from the manufacturing site, the extension of the overall construction time of the parking structure or, conversely, the immobilisation of the precast products on the manufacturing site and/or the need to have a high number of metal formworks available. Actually, the transportation of precast reinforced concrete slabs of suitable size for them to be utilised as modular elements of raised decks of rapidly assemblable parking structures is quite expensive: normally, no more than twelve elements can be loaded in each container, with resulting multiplication of the transport runs as well as of the costs connected with the installation of such structures far away from the manufacturing site.
As far as the precasting problems are concerned, it is apparent that, in order to fulfil in a short time the production request for a work having the size of a parking lot, it is necessary to have a large number of formworks available for simultaneous utilisation, this requiring a large working surface available on the production site and, in addition, a remarkable capital investment for producing the formworks. On the other hand, having recourse to any advanced production of the workpieces necessarily requires a large storage area and a remarkable capital immobilisation, in addition to raising the problem of production flexibility in respect of any xe2x80x9cnon standardxe2x80x9d size of the requested slabs.
As far as the latter problem is concerned, it should be noted that not only the size of the requested modular elements is subject to variations due to the foregoing reasons, but, in addition, a further variable aspect is introduced by the possibility of coating the concrete slab with either a layer of bituminous material or a thin film of protective resin. Since, for obvious reasons of wear resistance, the concrete slab is provided with a peripheral, built-in metal section, it is necessary to foresee in the precast production a top layer not filled with concrete having a thickness variable according to the circumstances.
A further drawback of the concrete modular floor described above has been found to be the unsatisfactory tightness of the junction between adjacent slabs as realised by a step joint with interposed sealing gasket. Actually, in this case the sealing of the step joint is effected after assembling the concrete panels and, as a joint of noticeable linear extension is involved, the possibility of defects and leakage is not negligible. Even if a final check of the tightness is performed by means of an xe2x80x9cartificial floodingxe2x80x9d upon installation, the possibility of settlement of the metal structure during the first period following installationxe2x80x94also due to the passage of the first vehiclesxe2x80x94does not offer any guarantee against possible seepage or leakage of water, that should be individually located and eliminated as they arise.
In view of the foregoing, it is an object of the present invention to provide a modular platform structure for raised decks suitable for bearing the load, in particular, of a vehicle parking lot, which structure can be easily and rapidly assembled when installing the work and can be equally easily disassembled, is reusable, durable and not subject to undue deterioration in use. In addition, such structure should allow to keep the transportation cost to a minimum when setting up the work and, although being readily demountable, should prevent any seepage or leakage of water towards the underlying area. Furthermore, the floor structure should allow a sufficient flexibility to be achieved with respect to the module size and to the type of final coating of the paving surface.
To achieve such purpose, this invention takes advantage of the conventional technology of construction of continuous load-bearing floors made of corrugated metal sheet filled with a layer ofxe2x80x94usually reinforcedxe2x80x94concrete, cast on the corrugated metal sheet. The latter acts both as a confining surface for the fluid concrete and as a component element of the final composite structure. According to the invention, each of the modular slab elements making up the raised deck can be directly and rapidly produced on the installation site by arranging a steel xe2x80x9cboxxe2x80x9d with a bottom of corrugated metal sheet and four walls formed by suitable metal sections (that, as such, are easily transportable and have adjustable dimensions) and by casting the concrete in such metal xe2x80x9cboxxe2x80x9d directly on the final location of the floor slab. In addition, according to this invention, the connections between the various slab elements forming the raised deck are not provided by sealing means aimed at preventing water from passing therethrough, but, on the contrary, they are entirely provided, on all sides of the slabs, by conveying means arranged for collecting such waterxe2x80x94rather than attempting to stop itxe2x80x94and for conveying it to the relevant drains.
Accordingly, the present invention specifically provides a demountable modular floor for raised decks consisting of modular quadrilateral units, each of which comprising:
a composite floor slab with a bottom element made of corrugated metal sheet (consisting of one or more pieces, according to the size) surrounded by four metal sections forming the side walls of said slab, and a layer of concrete cast on said bottom element of corrugated metal sheet and confined by said side walls, said metal sections forming said side walls having a cross-section substantially in the shape of a Z or of an S with square loops, and
four segments of upwardly open gutters, peripherally arranged around said composite floor slab and adjacent to said side wall sections, housed in the channels defined by pairs of side wall sections belonging to adjacent composite floor slabs.
Preferably, the upper, substantially horizontal, side of each of said Z-shaped or square loop S-shaped side wall sections is prolonged by a fin that is bent downwards and overhangs the respective gutter, so as to act as a drip. Such an arrangement allows the water flowing on the horizontal upper side of said side wall sections to vertically drop in the collecting gutter placed therebelow, rather than adhering to and flowing on the section extrados.
According to a preferred embodiment of this invention, the side wall sections of the composite slab that are parallel to the fold lines of said corrugated metal sheet of the bottom element have a substantially Z-shaped cross-section and the corresponding gutter segments are interposed between the vertical external sides of two of said Z-shaped side wall sections belonging to adjacent composite floor slabs. Again according to a preferred embodiment, the side wall sections that are orthogonal to the fold lines of said corrugated metal sheet have a substantially S-shaped cross-section with square loops, and the corresponding gutters are laid upon the intermediate, substantially horizontal, sides of two of said square loop S-shaped side wall sections belonging to adjacent composite floor slabs.
Further structural and functional features of the modular floor according to the invention are specified in the further dependent claims. According to another aspect thereof, this invention further provides, in addition to the final floor structure that can be realised by exploiting the above criteria, the set of elements that are assembled on the work site for building the raised deck, to be completed by simply casting concrete and subsequently applying a protective coating thereon. Therefore, the present invention also specifically provides an assemblable system on the work site for setting up demountable modular floors for raised decks consisting of quadrilateral modular units, which system comprises:
for each of said modular units, a quadrilateral element made of corrugated metal sheet (consisting of one or more pieces, according to the size) and four metal sections each having a length corresponding to one side of said corrugated metal sheet element, said metal sections having a cross-section substantially in the shape of a Z or of an S with square loops, each of said metal sections being suited to be coupled to a corresponding side of said corrugated metal sheet element;
two segments of main upwardly open gutters, suited to extend along one or more of said modular units and to be housed in the channels defined by pairs of metal sections belonging to adjacent modular units; and
two secondary upwardly open gutters, each having a length corresponding to one modular unit, suited to be housed in the channels defined by pairs of metal sections belonging to adjacent modular units.
It will be apparent that, even if it can be advantageously transported as separate component elements and assembled for casting concrete directly on the work site, the system of this invention can also be utilised, according to any specific requirements, for manufacturing the composite floor slabs away from the installation site, e.g., directly in the factory or in a suitable area within the building yard.